I like it and it's clean and simple. It did take me a minute or two to figure out it was a skateboard so maybe better clarity or a different angle would have more impact?

The angle of the dog is okay but he does seem a little flat. I'm not sure if it's his left leg or his tail that seems a little awkward.

Another idea if you don't go with the dog is multiple characters. Cartoons are about creativity so cartoon animals, people, etc. all merging together and bursting off the page is what I think of cartoons. I for one would be interesting in seeing a group shot with dogs, cats, girls, boys, robots, etc. all bursting off the page in a single shot but that might not be what you're going for.